1989 90 HP Yamaha 2 Stroke (ETLF) Excessive Smoke

[FishNowWorkLater]

I'm back...with more problems. I now have 2 stroke oil draining out the exhaust / prop. The tank level has definitely gone down and I haven't ran it since my first post here. This is what was happening all along I'm sure...but how?

The check valves are all good - the carbs are off and I can see the ports where the oil is injected into the intake, it's completely dry so it's not coming from the oil injection ports.

There is an O ring that is behind the oil pump, I'm guessing that is to keep oil from leaking around the oil pump? Is it there for any other purpose, like leaking into the engine where the oil pump is connected to whatever spindle makes the pump spin? Just taking shots in the dark at this point.

[99yam40]

I would think if that o ring is not holding the oil would drain down the drive shaft.
drop the lower unit and see if the shaft is covered in oil

[FishNowWorkLater]

I would think if that o ring is not holding the oil would drain down the drive shaft.
drop the lower unit and see if the shaft is covered in oil

Just went out and pulled the air box off again, it's filled with 2 stroke oil. It's pouring out the bottom carb even with the oil line into the bottom carb disconnected.

(Edit: I'll drop the lower unit as well and check)

[99yam40]

Just went out and pulled the air box off again, it's filled with 2 stroke oil. It's pouring out the bottom carb even with the oil line into the bottom carb disconnected.

(Edit: I'll drop the lower unit as well and check)

I do not understand how that can happen if the oil line was disconnected ,
unless there is a bunch up inside carb already and is still draining out of the carb throat

[FishNowWorkLater]

I found the leak, it's the oil seal around the shaft on the oil pump. I dropped the lower unit and there is oil all over the drive shaft.

Also there is one more O ring to replace in addition to the one on the oil pump. They look fine but they are going to get replaced as well. See below.

Oil draining out of the bottom carb

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After pulling the oil pump off, there is a concaved grommet (distance collar #19) and on the back side of it is another O ring

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2 Stroke oil inside of the hole on the powerhead where the gear shaft for the oil pump goes into. How in the world does this get from here to the bottom carb?

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Leaking oil seal on the oil pump ~ 2psi with soapy leak detector. This is where the oil source is coming from. Unless someone tells me otherwise, I can't imagine this is good.

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What do you all think, this is the issue? I don't get how the oil can travel from here to the bottom carb...

[FishNowWorkLater]

One more of the oil seal on the pump itself

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[FishNowWorkLater]

New oil pump and O rings ordered. I should be fishing by this weekend

[FishNowWorkLater]

I do not understand how that can happen if the oil line was disconnected ,
unless there is a bunch up inside carb already and is still draining out of the carb throat

Any idea on how that oil can get from that area to the bottom carb? I'm tempted to go pour 2 stroke oil in there and see if it continues to pour out the carb. It's no longer doing it obviously as I have the oil tank emptied and disconnected.

[FishNowWorkLater]

Just in case this helps anyone else - I replaced the oil pump and the 2 O rings - the smoking has completely stopped and no more 2 stroke oil coming out of the carbs or exhaust. It appears that the oil seal (not the o rings) on the oil pump was bad. There is no part available to replace just the seal so a new pump was required.

[99yam40]

thanks for updating your thread on the fix,
I am sure it will help someone searching in the future

[robert graham]

Guess you were lucky to even find a new oil pump for a motor that old…but thanks for sharing your experience and the fix….